1. Technical Field
This invention generally relates to sleep efficiency devices, and more specifically to a device and method for monitoring a person's sleep patterns through the person's physiological characteristics, determining an efficient sleep pattern, establishing a rapport between the person and a sleep guide, and guiding the person through one or more sleep patterns.
2. Background Art
Research indicates that a healthy adult sleeps an average of 7.5 hours each night and that most people sleep between 6.5 and 8.5 hours per night. Scientists do not know every facet of the sleeping process. However, researchers have determined that the sleeping process is a predictable cycle whose intervals are observable and may be monitored and examined clinically with polysomnography. Polysomnography provides data regarding electrical and muscular states during sleep.
Tracking the brain waves of sleepers using electroencephalographs (EEGs), researchers have currently identified and labeled six stages of sleep (including a pre-sleep stage), each stage characterized by distinctive brain-wave frequencies and patterns, as well as other physiological characteristics. Stage 0 is the pre-sleep stage and is characterized by low amplitude, high frequency alpha waves in the brain. At this stage, a person becomes relaxed, drowsy, and closes their eyes. Stages 1 through 4 are sometimes called non-rapid eye movement sleep (“NREM” sleep). Stage 1 is characterized by the sleeper's eyes rolling, and rhythmic alpha waves which give way to irregular theta waves that are lower in amplitude and have a lower frequency as the person loses responsiveness to stimuli. Stage 1 may last for five or ten minutes. Stage 2 is characterized by slower, larger brain waves punctuated by high frequency bursts of brain activity called sleep spindles which are marked by muscle tension. Stage 2 sleep is accompanied by a gradual decline in heart rate, respiration and temperature as the body prepares to enter deep sleep. Stages 3 and 4 normally occur 30 to 45 minutes after falling asleep. In Stage 3, there are fewer sleep spindles, but high amplitude and low frequency delta waves appear. Stage 4 is characterized by the high amplitude and low frequency delta waves appearing more than 50 percent of the time. The delta waves identify the deepest levels of sleep, when the heart rate, body temperature, respiration and blood flow to the brain are dramatically reduced, and growth hormones are secreted in the body. A person roused from Stage 4 sleep will be groggy and confused. Altogether, it takes between 30 and 120 minutes to complete NREM sleep. The pattern of the normal sleep cycle is: Stage 1, 2, 3, 4, 3, 2, Rapid Eye Movement Sleep. This cycle may repeat (often omitting Stage 1 during subsequent cycles), until a sleeper is awakened or sleep is disrupted. If the sleeper returns back to sleep, the stages may begin again, failing to complete the cycle.
Rapid eye movement sleep (“REM” sleep) makes up about 20 percent of sleep time. After REM sleep has begun, it is interspersed with NREM sleep every 30 to 40 minutes through the night. It is during REM sleep that dreams are experienced. In the REM sleep stage, the same fast frequency, low-amplitude beta waves that characterize waking states occur, and a person's physiological signs—heart rate, breathing, and blood pressure—also resemble those in the waking state. However, muscle tone decreases to the point of paralysis, with sudden twitches, especially in the face, hands and legs. REM sleep periods may last from 10 minutes at the beginning of a sleep cycle to one hour at the end of it.
Research has found that most people complete four to six complete sleep cycles each night, with each cycle lasting about 90 to 100 minutes. These cycles vary in composition, however; early in the night most of the time is spent in Stage 3 and 4 sleep, with Stage 2 and REM sleep predominating later on. Sleep patterns also may vary in the course of a person's life. On the average, an infant sleeps about 16 hours a day, in contrast to a 70-year-old who sleeps only about six hours a day. While REM sleep comprises about half of total sleep at birth, it eventually decreases to only about 25 percent of total sleep in old age. Sleeping patterns also vary greatly among individuals, and even among different cultures (in terms of napping, for example).
Regardless of the optimal sleep cycle or pattern for any particular person, many people have difficulty sleeping, are awakened in the middle of a sleep cycle, or otherwise do not have optimal sleep or do not use their sleep time as well as they could. To overcome sleep-related problems, many sleepers take sleep inducing or assisting drugs, attend psychological therapy, try relaxing techniques prior to sleeping, or just deal with not sleeping well. Many other sleepers do not realize they are not sleeping well and are, nonetheless, suffering the consequences of inefficient sleep. It would be advantageous to many sleepers to have a method for obtaining efficient sleep periods regardless of the person, their environment, and the time available for sleep.